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Evidence of surfactant deficiency in persistence of the fetal circulation
Insights
Phospholipid analysis in tracheal aspirates revealed surfactant deficiency in some cases of persistent fetal circulation (PFC), similar to respiratory distress syndrome (RDS). This finding suggests a role for surfactant in PFC pathogenesis.
Area of Science:
- Neonatology
- Pulmonary Medicine
- Biochemistry
Background:
- Persistence of fetal circulation (PFC) is a condition where newborns experience hypoxemia despite high oxygen levels.
- Pulmonary parenchymal changes are minimal in PFC, but echocardiograms show increased pulmonary arterial pressure.
Purpose of the Study:
- To compare phospholipid profiles in tracheal aspirates of infants with PFC, respiratory distress syndrome (RDS), and other severe neonatal diseases.
- To investigate the role of surfactant deficiency in the pathogenesis of PFC.
Main Methods:
- Analysis of phospholipid composition in tracheal aspirates.
- Comparison of phospholipid profiles between PFC, RDS, and other neonatal conditions.
- Assessment of mechanical ventilation effects on oxygenation.
Main Results:
- Infants with PFC showed low phosphatidylglycerol (PG) and low lecithin/sphingomyelin (L/S) ratio, similar to RDS.
- Phosphatidylinositol levels were higher in PFC compared to RDS.
- Phospholipid composition in other severe neonatal diseases resembled normal newborns with present PG and high L/S ratio.
Conclusions:
- Surfactant deficiency appears to be a contributing factor in the pathogenesis of some PFC cases.
- Mechanical ventilation may improve oxygenation in PFC partly by stabilizing peripheral airways.
Abstract:
The phospholipids of tracheal aspirates in persistence of the fetal circulation (PFC) were compared to those in the respiratory distress syndrome (RDS) and those in other severe diseases of the newborn. The infants with PFC were hypoxemic despite 80 to 100% inspiratory oxygen. There were small, if any, pulmonary parenchymal changes in radiographs. Echocardiograms demonstrated evidence of increased pulmonary arterial pressure. Mechanical ventilation increased arterial oxygen tension in each case. However, five of the eight patients required ventilation at a high frequency (57-65 min) and long inspiratory time (0.6--0.7 s). The phospholipids in tracheal aspirates in PFC were quite similar to those in RDS, namely there was a small amount, if any, phosphatidylglycerol (PG), and the lecithin/sphingomyelin (L/S) ratio was low. However, phosphatidylinositol was higher in PFC than in RDS. In the other diseases studied, the phospholipid composition resembled that of the normal newborn, namely PG was present and the L/S ratio was high. Surfactant deficiency seems to be important in the pathogenesis of some cases of PFC. The favorable effect of mechanical ventilation may be partly due to the stabilization of peripheral airways.